Pancreatic Acinar Cells Research Articles

MRG15 promotes cell apoptosis through inhibition of mitophagy in hyperlipidemic acute pancreatitis.

Hyperlipidemia is a common cause of acute pancreatitis (AP), often leading to more severe clinical symptoms. The mortality factor 4-like protein 1 (MORF4L1, also called MRG15) plays a crucial role in regulating lipid metabolism. Therefore, this study aimed to explore the mechanism of MRG15 in hyperlipidemic acute pancreatitis (HAP). Mendelian randomization, transcriptome analysis, and single-cell analysis were employed to explore the association between MRG15 and AP by utilizing publicly available databases. In vivo, hypertriglyceridemia mouse models were created by intraperitoneal injection of P407 or using APOE-deficient mice. Subsequently, the HAP model was induced by cerulean. In vitro, a cell model of HAP was established by initially exposing cells to palmitic acid to simulate a high-fat environment, followed by cerulein treatment. Subsequently, MRG15-related indicators were measured. Through Mendelian randomization, it was discovered that there is a positive correlation between genetic expression of MRG15 and the risk of AP. Transcriptome and single-cell analysis revealed that elevated MRG15 expression in AP contributes to lipid metabolism disorders and the activation of apoptosis pathways in pancreatic acinar cells. MRG15 is found to be significantly upregulated in cases of HAP. Knocking down MRG15 led to an increase in mitophagy and a decrease in apoptosis in pancreatic cells, and this effect was reversed when the mitochondrial Tu translation elongation factor (TUFM) was simultaneously knocked down. MRG15 inhibits mitophagy by degrading TUFM, ultimately promoting cell apoptosis and worsening the progression of HAP.

Pharmacological Inhibition of Phosphoglycerate Kinase 1 Reduces OxiDative Stress and Restores Impaired Autophagy in Experimental Acute Pancreatitis.

Damage to pancreatic acinar cells (PAC) and intracellular metabolic disturbances play crucial roles in pancreatic necrosis during acute pancreatitis (AP). Phosphoglycerate kinase 1 (PGK1) is a crucial catalytic enzyme in glycolysis. However, the impact of PGK1-involving glycolysis in regulating metabolic necrosis in AP is unclear. Transcriptome analysis of pancreatic tissues revealed significant changes in the glycolysis pathway and PGK1 which positively correlated with the inflammatory response and oxidative stress injury in AP mice. Furthermore, we observed a substantial increase in PGK1 expression in damaged PAC, positively correlating with PAC necrosis. Treatment with NG52, a specific PGK1 inhibitor, ameliorated pancreatic necrosis, inflammatory damage, and oxidative stress. Transcriptomic data before and after NG52 treatment along with the Programmed Cell Death database confirmed that NG52 protected against PAC damage by rescuing impaired autophagy in AP. Additionally, the protective effect of NG52 was validated following pancreatic duct ligation. These findings underscore the involvement of PGK1 in AP pathogenesis, highlighting that PGK1 inhibition can mitigate AP-induced pancreatic necrosis, attenuate inflammatory and oxidative stress injury, and rescue impaired autophagy. Thus, the study findings suggest a promising interventional target for pancreatic necrosis, offering novel strategies for therapeutic approaches to clinical AP.

Role of Sphingosine-1-Phosphate Signaling Pathway in Pancreatic Diseases

Sphingosine-1-phosphate (S1P) is a sphingolipid metabolic product produced via the phosphorylation of sphingosine by sphingosine kinases (SPHKs), serving as a powerful modulator of various cellular processes through its interaction with S1P receptors (S1PRs). Currently, this incompletely understood mechanism in pancreatic diseases including pancreatitis and pancreatic cancer, largely limits therapeutic options for these disorders. Recent evidence indicates that S1P significantly contributes to pancreatic diseases by modulating inflammation, promoting pyroptosis in pancreatic acinar cells, regulating the activation of pancreatic stellate cells, and affecting organelle functions in pancreatic cancer cells. Nevertheless, no review has encapsulated these advancements. Thus, this review compiles information about the involvement of S1P signaling in exocrine pancreatic disorders, including acute pancreatitis, chronic pancreatitis, and pancreatic cancer, as well as prospective treatment strategies to target S1P signaling for these conditions. The insights presented here possess the potential to offer valuable guidance for the implementation of therapies targeting S1P signaling in various pancreatic diseases.

Inducible, but not constitutive, pancreatic REG/Reg isoforms are regulated by intestinal microbiota and pancreatic diseases.

The REG / Reg gene locus encodes for a conserved family of potent antimicrobial but also pancreatitis-associated proteins. Here we investigated whether REG/Reg family members differ in their baseline expression levels and abilities to be regulated in the pancreas and gut upon perturbations. We found, in human and mouse, pancreas and gut differed in REG / Reg isoform levels and preferences, with duodenum most resembling the pancreas. Pancreatic acinar cells and intestinal enterocytes were the dominant REG producers. Intestinal symbiotic microbes regulated the expression of the same, select Reg members in gut and pancreas. These Reg members had the most STAT3-binding sites close to the transcription start sites and were partially IL-22 dependent. We thus categorized them as "inducible" and others as "constitutive". Indeed, also in models of pancreatic-ductal adenocarcinoma and pancreatitis, only inducible Reg members were upregulated in pancreas. While intestinal Reg expression remained unchanged upon pancreatic perturbation, pancreatitis altered the microbial composition of the duodenum and feces shortly after disease onset. Our study reveals differential usage and regulation of REG / Reg isoforms as a mechanism for tissue-specific innate immunity, highlights the intimate connection of pancreas and duodenum, and implies a gut-to-pancreas communication axis resulting in a coordinated Reg response.

Fecal glycoprotein 2 is a marker of gut microbiota dysbiosis and systemic inflammation

BackgroundAntimicrobial autoantigenic glycoprotein 2 (GP2) is an important component of the innate immune system which originates from the exocrine pancreas as well as from the small intestines. The relationship of GP2 with the intestinal microbiome as well as the systemic implications of increased fecal GP2 levels are, however, still unclear. Therefore, fecal samples from 2,812 individuals of the Study of Health in Pomerania (SHIP) were collected to determine GP2 levels (enzyme-linked immunosorbent assay) and gut microbiota profiles (16 S rRNA gene sequencing). These data were correlated and associated with highly standardised and comprehensive phenotypic data of the study participants.ResultsFecal GP2 levels were increased in individuals with higher body mass index and smokers, whereas lower levels were found in case of preserved exocrine pancreatic function, female sex or a healthier diet. Moreover, higher GP2 levels were associated with increased serum levels of high-sensitivity C-reactive protein, loss of gut microbial diversity and an increase of potentially detrimental bacteria (Streptococcus, Haemophilus, Clostridium XIVa, or Collinsella). At the same time, predicted microbial pathways for the biosynthesis of beneficial short-chain fatty acids or lactic acid were depleted in individuals with high fecal GP2. Of note, GP2 exhibited a stronger association to overall microbiome variation than calprotectin.ConclusionFecal GP2 is a biomarker of gut microbiota dysbiosis and associated with increased systemic inflammation. The intestines may be more important as origin for GP2 than pancreatic acinar cells. Future studies need to investigate the potential clinical value in disease specific patient cohorts.

Application of LEF-1 immunohistochemical staining in the diagnosis of solid pseudopapillary neoplasm of the pancreas

IntroductionSolid pseudopapillary neoplasm (SPN) is a tumor of young females with gain-of-function mutation in catenin beta 1 gene involved in Wnt signal transduction pathway. Beta-catenin immunohistochemistry (IHC) is used to diagnose SPN. Lymphoid enhancer-binding factor 1 (LEF-1) has been recognized in the transactivation of Wnt pathway. We aim to study LEF-1 IHC in SPN and other pancreatic tumors and compare it with beta-catenin IHC. MethodsWe retrieved cases of SPN, pancreatic neuroendocrine tumor (PanNET), serous cystadenoma (SCA), ductal adenocarcinoma (PDAC) and acinar cell carcinoma (ACC) from 2011 to 2023. Formalin-fixed, paraffin-embedded blocks with adequate tumor were cut and stained with beta-catenin (B-Catenin-1 clone) and LEF-1 (EP310 clone) IHC. Cases were reviewed by two pathologists independently. Nuclear staining with LEF-1 and beta-catenin was considered as positive. ResultsOur cohort consisted of 111 cases [SPN = 59 (42 resections, 11 FNA, 6 biopsies), PDAC = 24, PanNET = 22, SCA = 5, ACC = 1]. For SPN cases male to female ratio was1:8. Age ranged from 9 to 81 years (average: 32 years). Pancreatic tail was the most common location (47 %) followed by head (28 %), body (19 %) and neck (6 %). Tumor size ranged from 1.0 to 12.2 cm (average: 5 cm). Among the SPN cases 57/59 demonstrated strong nuclear LEF-1 staining. 2/49 cases were negative for LEF-1 (both pathologist in agreement). All SPN tumors demonstrated nuclear staining with beta-catenin. Among the non-SPN tumors, beta-catenin showed nuclear staining in 2/52 cases (2 PDAC). The remaining 50 cases were negative for nuclear beta-catenin and demonstrated variable staining pattern with interpretation variability between the two pathologists. The sensitivity and specificity for LEF-1 were 97 % and 100 %, respectively, while for beta-catenin, they were 100 % and 96 % respectively. ConclusionCrisp nuclear staining of LEF-1 without background staining makes diagnostic interpretation relatively easy and accurate compared to beta-catenin IHC. This is further helpful for small biopsy samples to help differentiate SPN from mimickers such as PanNET. None of the non-SPN cases displayed nuclear LEF-1 rendering it a valuable adjunct to beta-catenin in the diagnostic evaluation of SPN.

Molecular and Clinical Features of Pancreatic Acinar Cell Carcinoma: A Single-Institution Case Series

Objectives: Acinar cell carcinoma (ACC) accounts for about 1% of pancreatic cancers. The molecular and clinical features of ACC are less characterized than those of pancreatic ductal adenocarcinoma. Methods: We retrospectively evaluated the clinical and molecular features of ACC patients who underwent germline and/or somatic molecular testing at The University of Texas MD Anderson Cancer Center from 2008 to 2022 and two cases from 2023–2024 who underwent RNA and TME analysis by Boston Gene. Patient information was extracted from our institutional database with the approval of the Institutional Review Board. Results: We identified 16 patients with available molecular testing results. Fourteen patients had metastatic disease, one had borderline resectable disease, and one had localized resectable disease at diagnosis. Fifteen patients were wild type for KRAS (one patient had unknown KRAS status). Somatic/germline mutations of DNA damage repair genes (BRCA1/2, PALB2, and ATM) were present in 5 of 12 patients tested for these genes. One patient was found to have RET fusion and responded favorably to selpercatinib for over 42 months. The median overall survival (OS) was 24 months for patients with metastatic disease. One of the additional two cases who underwent BostonGene testing was found to have NTRK1 fusion. RNA and TME analysis by Boston Gene of the two cases reported immune desert features and relatively lower RNA levels of CEACAM5, CD47, CD74, and MMP1 and higher RNA levels of CDH6 compared with PDAC.

8182 New Mouse Model Mirrors Human MODY8: Opening Doors to Understanding Exocrine-Endocrine Crosstalk in the Diabetic Pancreas

Abstract Disclosure: K. El Jellas: None. V. Salerno: None. L.S. Katz: None. J. Hu: None. G. Fogarty: None. A. Mandal: None. A. DiStefano-Forti: None. D. Scott: None. M. Lowe: None. A. Molven: None. R.N. Kulkarni: None. Maturity-onset diabetes of the young, type 8 (MODY8) is a dominantly inherited form of monogenic diabetes, caused by heterozygous mutations in the carboxyl ester lipase (CEL) gene expressed in pancreatic acinar cells. MODY8 is characterized by chronic pancreatitis and exocrine dysfunction. Despite the intimate anatomical relationship between the endocrine and exocrine pancreas, little is known about the biological components mediating exocrine-endocrine communication in regulating glucose homeostasis. Here, we report a refined mouse model that bears the mutation present in MODY8 patients on one allele, and the humanized normal variable number of tandem repeat (VNTR) of CEL with 16 repeats (16R) on the other, mimicking the genetic make-up seen in MODY8 patients. Examination of glucose homeostasis revealed that inducing stress (e.g. by high-fat diet) leads to glucose intolerance in MODY8/16R mice and a blunted glucose-stimulated insulin-secretion compared to their control littermates. Histopathological analyses demonstrated features of chronic pancreatitis in some pancreatic lobes, including inflammation, acinar atrophy, acinar-to-ductal metaplasia, fibrosis and fat infiltration, mirroring the morphology of the human disease. Moreover, we applied immunolabeling-enabled three-dimensional imaging of solvent-cleared organs (iDISCO) to intact pancreata and found that beta-cell mass was significantly decreased in the MODY8/16R mice, with a large number of islets located within fatty lobes. These results are coupled with comparative proteomics and lipidomic profiling with the aim of understanding the molecular signatures of exocrine and endocrine cells during pathogenesis. In conclusion, we have generated a mouse that recapitulates several features of the exocrine and endocrine phenotype characteristic of human MODY8. This novel model provides a unique opportunity, not possible in humans, to characterize pancreatic endocrine-exocrine communication in a longitudinal manner as a response to diverse environmental stressors. Presentation: 6/2/2024

Proteomic basis for pancreatic acinar cell carcinoma and pancreatoblastoma as similar yet distinct entities

Acinar cell carcinoma (ACC) and pancreatoblastoma (PBL) are rare pancreatic malignancies with acinar differentiation. Proteogenomic profiling of ACC and PBL revealed distinct protein expression patterns compared to pancreatic ductal adenocarcinoma (PDAC) and benign pancreas. ACC and PBL exhibited similarities, with enrichment in proteins related to RNA processing, chromosome organization, and the mitoribosome, while PDACs overexpressed proteins associated with actin-based processes, extracellular matrix, and immune-active stroma. Pathway activity differences in metabolic adaptation, epithelial-to-mesenchymal transition, and DNA repair were characterized between these diseases. PBL showed upregulation of Wnt-CTNNB1 and IGF2 pathways. Seventeen ACC-specific proteins suggested connections to metabolic diseases with mitochondrial dysfunction, while 34 PBL-specific proteins marked this pediatric cancer with an embryonic stem cell phenotype and alterations in chromosomal proteins and the cell cycle. This study provides novel insights into the proteomic landscapes of ACC and PBL, offering potential targets for diagnostic and therapeutic development.

Cholic acid activation of GPBAR1 does not induce or exacerbate acute pancreatitis but promotes exocrine pancreatic secretion

Obstruction of bile ducts due to gallstones can lead to biliary acute pancreatitis (BAP). According to Perides et al., G protein-coupled bile acid receptor-1 (GPBAR1) mediates BAP. However, Zi’s findings suggest that GPR39, rather than GPBAR1, mediates TLCAS-induced increases in cytosolic calcium and acinar cell necrosis, casting doubt on the role of GPBAR1 in BAP. Numerous G protein-coupled receptors on pancreatic acinar cells utilize Ca2+ and cyclic adenosine monophosphate (cAMP) as second messengers to manage pancreatic exocrine secretion, with significant cross-talk between these signals. The primary bile acid cholic acid (CA) and its conjugated forms are predominant in the human gallbladder. This study aimed to clarify the role and physiological significance of GPBAR1 by investigating the physiological and pathological effects of CA activation on GPBAR1 in pancreatic acinar cells. Isolated rat pancreatic acinar cells were treated with CA and CCK in vitro to observe the effect of CA-induced cAMP signaling on CCK-induced physiological and pathological calcium signaling. In vivo evaluations involved reverse biliopancreatic duct injections of 5% sodium taurocholate (STC) or 5% CA in rats. CA induced intracellular cAMP signaling in a concentration-dependent manner without increasing the intracellular Ca2+ concentration. CA did not independently cause calcium overload or enzyme activation, nor did it exacerbate calcium overload or enzyme activation from high-dose CCK. Reverse biliopancreatic duct injections of 5% CA did not cause acute pancreatitis in the rats. Transcriptomic analysis revealed that 50 μM CA induced changes in gene expression related to protein synthesis in the endoplasmic reticulum and ribosomes. Furthermore, 50 μM CA accelerated the calcium waves and increased the enzyme secretion induced by CCK. GPBAR1 was found on the basolateral membrane in rat pancreatic tissue rather than near the apical region of acinar cells.GPBAR1 activation is not crucial for BAP activity but may play a role in bile acid regulation of pancreatic exocrine secretion, suggesting that GPBAR1 is a potential therapeutic target for pancreatic exocrine insufficiency.

Inhibition of Ribosome Biogenesis in vivo Causes p53-Dependent Death and p53-Independent Dysfunction.

Ribosomes are critical for cell function; their synthesis (known as ribosome biogenesis; "RiBi") is complex and energy-intensive. Surprisingly little is known about RiBi in differentiated cells in vivo in adult tissue. Here, we generated mice with conditional deletion of Nat10 , an essential gene for RiBi and translation, to investigate effects of RiBi blockade in vivo. We focused on RiBi in a long-lived, ribosome-rich cell population, pancreatic acinar cells, during homeostasis and tumorigenesis. We observed a surprising latency of several weeks between Nat10 deletion and onset of structural and functional abnormalities and p53-dependent acinar cell death, which was associated with translocation of ribosomal proteins RPL5 and RPL11 into acinar cell nucleoplasm. Indeed, deletion of Trp53 could rescue acinar cells from apoptotic cell death; however, Nat10 Δ / Δ ; Trp53 Δ / Δ acinar cells remained morphologically and functionally abnormal. Moreover, the deletion of Trp53 did not rescue the lethality of inducible, globally deleted Nat10 in adult mice nor did it rescue embryonic lethality of global Nat10 deletion, emphasizing p53-independent consequences of RiBi inhibition. Deletion of Nat10 in acinar cells blocked Kras -oncogene-driven pancreatic intraepithelial neoplasia and subsequent pancreatic ductal adenocarcinoma, regardless of Trp53 mutation status. Together, our results provide initial insights into how cells respond to defects in RiBi and translation in vivo .

Large-scale multi-omic analysis identifies noncoding somatic driver mutations and nominates ZFP36L2 as a driver gene for pancreatic ductal adenocarcinoma.

Identification of somatic driver mutations in the noncoding genome remains challenging. To comprehensively characterize noncoding driver mutations for pancreatic ductal adenocarcinoma (PDAC), we first created genome-scale maps of accessible chromatin regions (ACRs) and histone modification marks (HMMs) in pancreatic cell lines and purified pancreatic acinar and duct cells. Integration with whole-genome mutation calls from 506 PDACs revealed 314 ACRs/HMMs significantly enriched with 3,614 noncoding somatic mutations (NCSMs). Functional assessment using massively parallel reporter assays (MPRA) identified 178 NCSMs impacting reporter activity (19.45% of those tested). Focused luciferase validation confirmed negative effects on gene regulatory activity for NCSMs near CDKN2A and ZFP36L2 . For the latter, CRISPR interference (CRISPRi) further identified ZFP36L2 as a target gene (16.0 - 24.0% reduced expression, P = 0.023-0.0047) with disrupted KLF9 binding likely mediating the effect. Our integrative approach provides a catalog of potentially functional noncoding driver mutations and nominates ZFP36L2 as a PDAC driver gene.

Dachaihu Decoction alleviates chronic pancreatitis by regulating MAPK signaling pathway: Insights from network pharmacology and experimental validation

Ethnopharmacological relevanceChronic pancreatitis (CP), a syndrome characterized by inflammatory fibrosis, can impair both the internal and external secretory functions of the pancreas. The global incidence of this disease is gradually increasing. However, the exact pathogenesis remains unclear, resulting in a lack of targeted clinical therapies. According to the principles of traditional Chinese medicine, CP can be attributed to Shaoyang and Yangming syndromes, which manifest as abdominal pain and hypochondriac distension. Dachaihu Decoction (DCHD) is a classic formula from the “Treatise on Febrile and Miscellaneous Disease.” It is frequently prescribed for conditions associated with combined Shaoyang and Yangming syndromes. However, the specific mechanisms by which DCHD prevents and treats CP remain unclear and require further investigation. Aim of the studyUsing a holistic methodology, including network pharmacology, molecular docking, transcriptomic profiling, and animal experimentation, we explored the potential therapeutic mechanisms of DCHD in CP. Materials and methodsIn a mouse model, caerulein was used to induce CP, and DCHD was administered via gastric lavage to assess its therapeutic effect on pancreatic injury caused by caerulein-induced CP. Subsequently, pancreatic tissues were collected for transcriptomic analysis. Screening of DCHD-active ingredient-target pathways for CP treatment was conducted using network pharmacology and further preliminary validation was performed using molecular docking techniques. Additionally, in vivo and in vitro validation was conducted using animal and cells experiments based on the predicted results. ResultsOur findings suggest that DCHD ameliorates pancreatic acinar cell injury, pancreatic inflammation, and fibrosis in mice with CP. Network pharmacology identified 385 potential targets of DCHD associated with CP. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the therapeutic effect of DCHD on CP may be linked to the mitogen-activated protein kinase (MAPK) signaling pathway. Transcriptomic data supported this finding, as it confirmed that DCHD inhibited the pancreatic MAPK signaling pathway in CP. Molecular docking studies further revealed that the top ten active components of DCHD exhibited strong docking activity with key molecules within the MAPK signaling pathway. Finally, animal experiments confirmed that DCHD effectively reduced the phosphorylation of P38, Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) in pancreatic tissues. In addition, the expression of p-P38, p-JNK, and p-ERK was reduced in pancreatic stellate cells and macrophages in the DCHD group. We further treated CP mice, human pancreatic stellate cell line (hPSCs), and macrophage cell line RAW264.7 with the active component baicalin from DCHD, and found that baicalin effectively reduced pancreatic damage in CP. Additionally, the expression of key proteins in the MAPK signaling pathway was significantly decreased in both hPSCs and RAW264.7. ConclusionIn summary, DCHD plays an important role in the treatment of chronic pancreatitis, and it may become a promising drug against the progression of CP. The role of DCHD in alleviating pancreatic inflammatory cell infiltration and fibrosis may be related to the regulation of the MAPK signaling pathway.

Abstract C076: Transcriptomic analyses of normal human pancreatic acinar cells reveal the presence of cancer subtypes that correlate with acinar ductal metaplasia

Abstract Gene expression subtypes exist in pancreatic ductal adenocarcinoma (PDAC), however comparable subtypes are not known to exist in normal human pancreas. Our laboratory has collected a large (N=55) and racially diverse (14 Black, 27 White and 14 Hispanic) cohort of normal human pancreatic acinar cell specimens that were processed at islet transplantation centers. Deceased organ donors were maintained on life support until the time the pancreas was surgically removed. Samples of primary, uncultured (Day 0) or ADM transdifferentiated (Day 6) normal pancreatic acinar cells were subjected to bulk transcriptomic sequencing. UMAP analysis of the transcriptomic data from the Day 0 samples revealed the presence of two distinguishable clusters of data that we arbitrarily refer to as Group 1 (n = 31) and Group 2 (n = 24). Heatmaps of the expression of 57 genes belonging to the exocrine-like, classical and basal subtypes produced a clear separation of the data. Since the exocrine-like genes increased in Group 1 and the basal and classical genes increased in Group 2, we refer to Group 1 as the exocrine-like subtype and Group 2 as the basal/classical subtype. The basal/classical subtype samples showed greater morphological and molecular acinar ductal metaplasia compared to those in the exocrine-like subtype. When stratified by demographics and subtype, volcano plots revealed a striking trend with Blacks, women, obese and younger individuals having significantly fewer differentially expressed genes (basal/classical vs exocrine-like) compared to Hispanics, men, nonobese and older individuals. Our data demonstrate that, similar to PDAC, normal pancreatic acinar cells are distinguishable by gene subtypes. Moreover, the gene expression ratio of these subtypes varies dramatically by donor demographics. Citation Format: Corey M Perkins, Jinmai Jiang, Zachary Greenberg, Md Abu Talha Siddique, Linda C Williams, Jason O Brant, Kalyanne Shirlekar, Bo Han, Jamel Ali, Kristianna M Fredenburg, Kiley Graim, Diana J Wilkie, Mei He, Thomas D Schmittgen. Transcriptomic analyses of normal human pancreatic acinar cells reveal the presence of cancer subtypes that correlate with acinar ductal metaplasia [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C076.

Computational Model of Complex Calcium Dynamics: Store Operated Ca2+ Channels and Mitochondrial Associated Membranes in Pancreatic Acinar Cells.

This proposed model explores the intricate Ca2+ dynamics within the pancreatic acinar cells (PACs) by emphasizing the role of store-operated Ca2+ entry (SOCE) and the mitochondrial-associated membranes (MAMs) in the secretory region (apical) of the PACs. Traditionally, Ca2+ releases from the endoplasmic reticulum (ER) via calcium-induced calcium release (CICR). It has been shown to be important in regulating functions such as secretion of digestive enzymes in PACs. However, this model posits that upon the depletion of Ca2+ in the ER, the signaling protein stromal interaction molecule (STIM1) is activated. Activated STIM1, then facilitates the opening of Orai channels, allowing Ca2+ influx through the store-operated calcium channels (SOCCs). The model highlights the complexity of the Ca2+ dynamics, and the importance of SOCE and MAMs in the PACs Ca2+ homeostasis. The numerical and bifurcation analysis illustrate how changes in agonist concentrations can lead to the diverse Ca2+ oscillation patterns, such as thin to broader oscillations, sinusoidal patterns, and baseline fluctuations, driven by the feedback mechanisms involving Ca2+ and inositol 1,4,5 trisphosphate (IP3). This understanding could have broader implications for cellular physiology and the development of therapies targeting Ca2+ signaling pathways.

Effect of long-term ethanol consumption and a high-fat diet on mitochondrial respiration in rat pancreatic acinar cells and hepatocytes

Chronic alcohol consumption may cause pancreatitis and alcohol-related liver diseases. Both adaptation and damage of liver mitochondria in animals on chronic ethanol and high-fat diets were demonstrated. It is currently not clear if ethanol or its metabolites such as fatty acid ethyl esters can cause mitochondrial damage to the pancreas. The present study aimed to evaluate the effect of chronic ethanol administration in combination with a high-fat diet on mitochondrial respiration in both pancreatic acinar cells and hepatocytes of rats. Wistar male rats on a high-fat diet (35% calories) were administered ethanol (6 g/kg body weight) by oral gavage for 14 days. Pancreatic acini cells and hepatocytes were isolated with collagenase digestion. The respiration of isolated cells was studied with a Clark electrode. Ethanol administration to rats kept on a high-fat diet was followed by a rapid loss of animal weight during the first 5 days of the experiment and diminished secretory response of pancreatic acini to acetylcholine, however, no changes in acinar cells ultrastructure, basal, oligomycin-insensitive or FCCP-uncoupled respiration were found. Meanwhile ethanol caused a significant (~40%) increase in basal and maximal FCCP-uncoupled respiration rate of isolated hepatocytes. In conclusion, chronic ethanol administration to rats on a high-fat diet does not cause mitochondrial damage in the pancreas, while mitochondria of the liver adapt to ethanol by increasing respiration rate. Keywords: ethanol, hepatocytes, high fat diet, mitochondrial respiration, pancreatic acinar cells

Mitochondrial DNA Leakage Promotes Persistent Pancreatic Acinar Cell Injury in Acute Pancreatitis viathe cGAS-STING-NF-κB Pathway.

Previous research has shown that the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway in macrophages can promote severe acute pancreatitis through the release of inflammatory factors. The role of this pathway in pancreatic acinar cells, however, has not been studied, and understanding its mechanism could be crucial. We analysed plasma from 50 acute pancreatitis (AP) patients and 10 healthy donors using digital PCR, which links mitochondrial DNA (mtDNA) levels to the severity of AP. Single-cell sequencing of the pancreas during AP revealed differentially expressed genes and pathways in acinar cells. Experimental studies using mouse and cell models, which included mtDNA staining and quantitative PCR, revealed mtDNA leakage and the activation of STING-related pathways, indicating potential inflammatory mechanisms in AP. In conclusion, our study revealed that the mtDNA-STING-nuclear factor κB(NF-κB) pathway in pancreatic acinar cells could be a novel pathogenic factor in AP.

Chaiqin chengqi decoction treatment mitigates hypertriglyceridemia-associated acute pancreatitis by modulating liver-mediated glycerophospholipid metabolism

BackgroundThe incidence of hypertriglyceridemia-associated acute pancreatitis (HTG-AP) is increasing globally and more so in China. The characteristics of liver-mediated metabolites and related key enzymes are rarely reported in HTG-AP. Chaiqin chengqi decoction (CQCQD) has been shown to protect against AP including HTG-AP in both patients and rodent models, but the underlying mechanisms in HTG-AP remain unexplored. PurposeTo assess the characteristics of liver-mediated metabolism and the therapeutic mechanisms of CQCQD in HTG-AP. MethodsMale human apolipoprotein C3 transgenic (hApoC3-Tg; leading to HTG) mice or wild-type littermates received 7 intraperitoneal injections of cerulein (100 μg/kg) to establish HTG-AP and CER-AP, respectively. In HTG-AP, some mice received CQCQD (5.5 g/kg) gavage at 1, 5 or 9 h after disease induction. AP severity and related liver injury were determined by serological and histological parameters; and underlying mechanisms were identified by lipidomics and molecular biology. Molecular docking was used to identify key interactions between CQCQD compounds and metabolic enzymes, and subsequently validated in vitro in hepatocytes. ResultsHTG-AP was associated with increased disease severity indices including augmented liver injury compared to CER-AP. CQCQD treatment reduced severity and liver injury of HTG-AP. Glycerophospholipid (GPL) metabolism was the most disturbed pathway in HTG-AP in comparison to HTG alone. In HTG-AP, the mRNA level of GPL enzymes involved in phosphocholine (PC) and phosphatidylethanolamine (PE) synthesis (Pcyt1a, Pcyt2, Pemt, and Lpcat) were markedly upregulated in the liver. Of the GPL metabolites, lysophosphatidylethanolamine LPE(16:0) in serum of HTG-AP was significantly elevated and positively correlated with the pancreas histopathology score (r = 0.65). In vitro, supernatant from Pcyt2-overexpressing hepatocytes co-incubated with LPE(16:0) or phospholipase A2 (a PC- and PE-hydrolyzing enzyme) alone induced pancreatic acinar cell death. CQCQD treatment downregulated PCYT1a and PCYT2 enzyme levels in the liver. Hesperidin and narirutin were identified top two CQCQD compounds with highest affinity docking to PCYT1a and PCYT2. Both hesperidin and narirutin reduced the level of some GPL metabolites in hepatocytes. ConclusionLiver-mediated GPL metabolism is excessively activated in HTG-AP with serum LPE(16:0) level correlating with disease severity. CQCQD reduces HTG-AP severity partially via modulating key enzymes in GPL metabolism pathway.

CTNNB1 exon 3 mutations in metastatic solid pseudopapillary neoplasm of the pancreas.

Solid pseudopapillary neoplasm (SPN) of the pancreas demonstrates an indolent disease course; however, some patients present with a "malignant" phenotype, including distant metastases resistant to chemotherapy. This analysis identifies molecular drivers of metastatic SPN using the world's largest clinicogenomics database. The American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange was queried for primary and metastatic SPN samples. Sample-level genomic alterations were compared. A pan-pancreatic cancer analysis assessed relevant mutations among all metastatic pancreatic malignancies. Among 28 SPN samples identified (n = 17 primary, n = 11 metastatic), the most commonly mutated gene was CTNNB1, (24/28 samples; 85.7%). Most mutations were missense (21/24; 87.5%) or in-frame deletions (3/24; 12.5%). The most common CTNNB1 mutations in primary SPN were exon 3 S37F/C missense mutations (6/16 profiled patients, 37.5%), contrasting exon 3 D32N/Y/H missense mutations in metastatic samples (6/11 profiled patients, 54.5%). Metastatic SPN had higher rates of CTNNB1 mutations than metastases from pancreatic ductal adenocarcinoma (72.7% vs. 1.1%; q < 0.0001), pancreatic neuroendocrine tumor (72.7% vs. 2.5%; q < 0.0001), and pancreatic acinar cell carcinoma (72.7% vs. 11.5%; q = 0.0254). Missense mutations along exon 3 of CTNNB1 predominate metastatic SPN, differentiating these patients from those with metastases from analogous pancreatic malignancies.

TFEB-Mediated Pro-inflammatory Response in Murine Macrophages Induced by Acute Alpha7 Nicotinic Receptor Activation.

Transcription factors TFEB and TFE3 are crucial for regulating autophagy, lysosomal biogenesis, and lipid metabolism, and have significant roles in macrophage function and innate immunity. The alpha7 nicotinic acetylcholine receptor (α7nAChR), a ligand-gated Ca 2+ channel known for its therapeutic potential in neurological and inflammatory disorders, has been implicated in modulating immune responses by modulating macrophage function. Stimulation of α7nAChR with chemical agonists has been claimed to activate TFEB in pancreatic acinar cells and neurons. However, the impact of α7nAChR activation on TFEB and TFE3 in macrophages remained unknown, posing an important question due to the potential implications for inflammation regulation. This study investigates the effects of acute α7nAChR activation on TFEB-mediated responses in murine macrophages using the specific agonist PNU-282987. We demonstrate that α7nAChR stimulation triggers TFEB nuclear translocation and lysosomal expansion. Surprisingly, PNU-282987 induces a broad pro-inflammatory gene signature without concomitant cytokine secretion, suggesting an uncoupling of gene expression from cytokine release. Mechanistically, TFEB activation requires the lysosomal Ca 2+ exporter MCOLN1 and the Ca 2+ -dependent phosphatase PPP3/calcineurin. Additionally, PNU-282987 elevates reactive oxygen species (ROS) levels, and ROS are involved in TFEB activation by PNU-282987. Notably, even with α7nAChR deletion, compensatory ROS-mediated TFEB activation persists, suggesting the involvement of additional nicotinic receptors. Our findings reveal a novel α7nAChR-TFEB signaling axis in macrophages, offer new insights into the cholinergic regulation of immune responses, establish a baseline for comparison with disease states, and identify potential therapeutic targets for modulating inflammation.